Use this calculator to estimate how much rain your roof might collect in a year and potentially how much
water storage you might need.

Choose the nearest Texas city:

Choose the type of roof:

Enter the roof footprint in square feet:

The roof footprint is the length times the width of the roof area without regard to the pitch.
If you don't know the roof foot print and your house is 1 storey, enter the house square footage plus eave overhangs.

or

Choose a roof size:

Small
Medium
Large

Store water for landscaping use only?

Store water for in house use only?

Store water for both house and landscape?

Enter your average monthly landscape water use in gallons:

Use your monthly water bills to estimate your average monthly water use for landscaping and household.
Compare the water bills from December - February to the water bills from May - October. The average difference between
the two time periods is a good estimate for your landscaping use. If you don't have your water bills, enter
3000.

Landscape water use, by default, covers May - October. If you water during other months, please select those months below.

January
February
March

April
November
December

Enter your average monthly household water use in gallons:

Use the average of your water bills from December - February to estimate household usage. If you don't have your water bills,
mutiply the number of people in the household by 50 and then by 30 (e.g. 2 adults and 1 child * 30 days = 4500 gallons).

Note: The numbers derived from this calculator are high-level estimates only and are meant only to give you an idea of
your catchment potential. The calculated storage amount needed assumes that you have no back-up water supply
and includes a 75 day cushion for dry periods.